Semi-automatic suture device for using surgical thread

ABSTRACT

The present invention provides an implantable device for semiautomatic suturing using a surgical thread, the suturing enabling biological and/or artificial tissues to be united, the device comprising: blocking means enabling two strands of the thread of a suture to be connected together in a blocking zone; a bearing element having a bearing surface for bearing against the tissues to be sutured together; and controlled tensioning means for applying controlled tensioning to said thread, and suitable, after the two strands of said thread have been blocked together using said blocking means, for exerting a tension at a first predetermined tension value, with the junction between said bearing element and said blocking zone of the device being provided by said controlled tensioning means.

The present invention relates to a semiautomatic implantable surgicaldevice for suturing with surgical thread. More particularly, the presentinvention relates to a suture device including blocking means forblocking together two strands of thread in a suture.

The present invention relates still more particularly to a device forsuturing by a minimally invasive surgical approach. Minimally invasivesurgery consists in making cutaneous and parietal incisions of smallsize and introducing instruments and viewing means such as a camera inorder to perform an operation in video-assisted manner through orificeshaving a diameter lying in the range 3 millimeters (mm) to 12 mm bymeans of a hollow cylindrical instrument referred to as a “trocar”.

BACKGROUND OF THE INVENTION

In minimally invasive surgery, anastomoses are often made using suturesof surgical thread secured by knots. Tying a knot on an organ or avessel constitutes a difficult step during surgery since:

-   -   any slackening of sutures can lead to complications that are        severe or even fatal;    -   tying knots while using a laparoscopic approach is technically        difficult; and    -   the increasing number of knots required increases the duration        of surgery in significant manner, and for certain operations,        such as those involving vascular clamping where operating time        must be kept very short, that can run the risk of leading to        operative or postoperative complications.

Proposals have been made to use clip or staple type devices, inparticular in U.S. Pat. No. 5,356,459 which seeks to replace suturethread in order to avoid the need to tie knots. Nevertheless, surgeonsprefer to use thread when suturing, since they have acquired automaticand habitual skills such that the sutures they make in this way aretried and tested. In addition, the reliability of clip or staple typedevices has yet to be validated.

OBJECTS AND SUMMARY OF THE INVENTION

That is why the present invention seeks to provide a device for suturingusing a thread, but offering an alternative to tying knots so as to makeit easier to connect two strands of suture thread together, and makingit possible significantly to reduce the time required for connectingsaid strands of thread together.

The inventors have discovered that one of the difficulties in tyingknots in suture thread lies in the need for the surgeon to exert tensionon the thread, firstly in order to tighten the suture prior to making apermanent connection between the two strands of thread, and secondly tomake it easier to tie the knot. One difficulty thus lies in the need forthe surgeon to control the tension to be exerted on the thread in orderto avoid tightening excessively, or conversely tighteninginsufficiently, which in both cases would lead to a suture that isineffective. Controlling thread tension and tying the knots themselvesare both acts that are difficult since they need to be done usingforceps that are long (20 centimeters (cm) to 30 cm), through trocars,and in a space that is confined. Excessively tightening the threads canlead to a thread itself breaking or to pinching of the biological tissuethat is to be repaired. Such pinching can lead to phenomena of tissuerupture or of inflammatory reaction. In contrast, when tightening is notsufficient, the junction between pieces of tissue or between a tissueand a prosthesis can be imperfect and the suture is not leaktight.

U.S. Pat. Nos. 5,669,917, 6,066,160, 6,077,277, 6,217,591, and 6,293,961propose various devices enabling two strands of thread to be connectedand blocked together instead of requiring the surgeon to tie knots.Nevertheless, in those prior devices, it is always necessary to put thethread under tension in order to tighten the suture before connectingand blocking together the two strands of thread. During this step, it isnot possible for the tension exerted on the thread by the surgeon to becontrolled automatically in any way.

In addition, in some of the proposed devices, the suture that is madecannot be easily undone, should that be necessary.

The object of the present invention is thus to provide a surgical suturedevice that is compatible with using conventional suture thread so as toconserve the benefits of conventional surgery and increase theconfidence of the surgeon, while remedying the drawbacks of priordevices.

In particular, an object of the present invention is to provide a suturedevice that makes it possible to block suture threads quickly andreliably in a manner that is semiautomatic for the surgeon.

Another object of the present invention is to provide a suture devicesuch that the suture made thereby is of reversible or removablecharacter, and in particular can be cut almost instantaneously withoutany risk of damaging the surrounding tissues.

For this purpose, the present invention provides a suture devicecomprising: blocking means for connecting together two strands of threadin a blocking zone; and controlled tensioning means for controlledtensioning of said thread, and suitable, after the two strands of saidthread have been blocked together using said blocking means, forexerting tension on the thread at a first predetermined tension value.

More precisely, the present invention provides an implantable device forsemiautomatic suturing using a surgical thread, the suturing enablingbiological and/or artificial tissues to be united, the devicecomprising: blocking means enabling two strands of the thread of asuture to be connected together in a blocking zone; a bearing elementhaving a bearing surface for bearing against the tissues to be suturedtogether; and controlled tensioning means for applying controlledtensioning to said thread, and suitable, after the two strands of saidthread have been blocked together using said blocking means, forexerting a tension at a first predetermined tension value, with thejunction between said bearing element and said blocking zone of thedevice being provided by said controlled tensioning means.

Two strands of thread are said herein to be “connected together” whenthe two strands cannot move relative to each other in said blockingzone, i.e. they are not necessarily in contact with each other in saidblocking zone.

The device can be used to unite pieces of biological tissue, one or morepieces of biological tissue with one or more pieces of artificialtissue, or solely pieces of artificial tissue.

In the device of the invention, said blocking means and said tensioningmeans are suitable for co-operating so that two strands of suture threadare blocked together before exerting said first predetermined tensionvalue, and once the two strands have been blocked together, the devicetensions the suture threads at said first predetermined tension value inautomatic manner.

Tensioning said suture thread enables the two pieces of tissue, or apiece of tissue and a prosthesis, that are to be united by said sutureto be moved together effectively by tightening the thread. Withprostheses, said tissue can be biological or artificial.

The term “controlled tensioning” is used herein to mean tensioning at asaid first known and predetermined tension value, which tensioning canbe applied automatically using said tensioning means, and no longerdepends on the initial tension exerted manually by the surgeon on thethread or on a device; that is why the device of the invention is saidto be “semiautomatic”.

The fact of tensioning the suture threads to a said first predeterminedtension value in controlled manner gives the device dynamometricbehavior and contributes to the effectiveness of the device and thespeed and ease of suturing using the device. The dynamometric behaviorof the device of the invention serves to ensure that tensioning isapplied appropriately, uniformly, reliably, and repetitively on thethreads that are to constitute the suture. Having tension that isuniform makes it possible to distribute forces evenly over the suturedtissues, and thus to minimize aggression to said tissues.

Said first predetermined tension value may preferably lie in the range0.1 newtons (N) to 10 N, depending on the site of surgery, i.e.depending on the type of tissue to be sutured and depending on the typeof suture thread used, and in particular it may be about 2 N whichcorresponds to the mean tension value of a suture made between a vesseland a vascular prosthesis during conventional surgery under goodoperating conditions.

In a preferred embodiment, the blocking of said strands of thread usingsaid blocking means is suitable for automatically triggering saidtensioning of the thread at a said first predetermined tension value,preferably lying in the range 0.1 N to 10 N.

More particularly, in a dynamometric suture device of the invention,said controlled tensioning means are suitable for co-operating with:

-   -   a bearing element having a bearing surface for bearing against        said tissue to be sutured in a zone (4 ₁) where the device        contacts said tissue; preferably in the proximity of suture        orifices in said tissue; and    -   said blocking means (2) in such a manner as to enable the        distance between said blocking zone and said zone of contact        between the device and the tissue to be adjusted between:        -   an initial distance (L) in which said blocking of the two            ends of the strands of thread can be performed with the            thread being at a tension that is preferably small; and        -   a final distance (L′=L±b) suitable for exerting a said            controlled tension at a said first predetermined tensioning            value.

Thus, if the tension exerted by the surgeon on the thread prior toblocking is less than said first predetermined tension value, then saidfinal distance (L+b) will be longer than said initial distance, andconversely if the tension exerted on the thread by the surgeon prior toblocking is greater than said predetermined tension, then said finaldistance (L−b) will be shorter than said initial distance.

Still more particularly, in a suture device of the invention, saidtensioning means for adjusting the distance between a said zone ofcontact on said tissue and said blocking zone, comprise said junctionmeans between said contact zone and said blocking zone.

Said first controlled tension value is thus achieved by adjusting thedistance between two zones, namely a contact zone and a blocking zone,by means of a junction element, which adjustment is a function both ofsaid initial distance between said two zones and of the initial tensionof the thread as exerted by the surgeon prior to blocking.

As mentioned above, tensioning the threads, and thus implementing saidadjusted distance between the contact zone and the blocking zone, ispreferably triggered automatically by causing said thread blocking meansto operate. Nevertheless, such triggering can be implemented manually bythe operator, particularly by relaxing a pressure being exerted by theoperator for maintaining said initial pressure manually.

The device of the invention is advantageously put into contact with thetissue to be sutured by means of a placing instrument known as an“ancillary”. The suture device of the invention is thus suitable forco-operating with said placing instrument to which it is secured priorto said blocking, preferably being secured via a top portioncorresponding to said blocking zone, and, where appropriate, tensioningof the thread after blocking may be triggered manually using saidplacing instrument.

In an embodiment, the placing instrument may also serve to cut the endsof the strands of suture thread over the thread blocking zone at adistance lying in the range 1 mm to 10 mm, and in particular 5 mm to 6mm from the blocking zone, after the threads have been blocked togetherand depending on the anatomatic site of the surgery.

In a preferred embodiment, said tensioning means comprise means forestablishing a resilient junction between said contact zone and saidblocking zone so as to enable the distance to be adjusted between:

-   -   a controlled initial distance (L) in which the spacing between        said contact zone and said blocking zone is controlled by a        first link element or a first spacer element, with said initial        distance (L) corresponding to a distance in which said blocking        zone and contact zone are in a close position obtained by        compression from a remote, rest position (L+a); and    -   said final adjusted distance (L′=L±b, b<a) which corresponds to        a force equilibrium position in which the distance between said        contact zone and said blocking zone is no longer controlled by a        said first link element or a said first spacer element.

The term “force equilibrium” is used herein to mean equilibrium betweenthe force exerted by the junction means and the tension of the suture.

Said first link element and/or said first spacer element may be securedto said placing instrument or to said suture device proper.

More particularly, said junction means are made of a material thatpresents elasticity, and said suture device is secured to the placinginstrument via said blocking zone such that:

-   -   when pressure is exerted on said blocking zone, it is possible,        where appropriate, to move said blocking zone from the natural,        rest position (L+a) of the device to said initial distance (L),        in which said blocking together of the two strands of thread can        be implemented under arbitrary tension as exerted on the suture        thread by the surgeon, and preferably under no tension; and    -   said tensioning of the suture thread exerted by the device of        the invention takes place after said blocking by returning said        blocking zone to a said adjusted final distance (L±b) on        releasing the pressure exerted on said blocking zone.

The blocking zone and the contact zone can be brought towards each otherto said initial distance (L) even before the threads are inserted intothe device. The device is then pre-stressed when in position in itsplacing instrument.

In a first variant embodiment, said initial distance may be obtainedusing a first link element such as a tab suitable for initiallyconnecting said blocking zone and said tissue contact zone, and saidadjusted final distance of said blocking zone relative to said contactzone can be implemented by releasing said first link element connectingtogether said blocking zone and said contact zone of the device.

Preferably, said first link element forms a part of said suture deviceof the invention, and release of said link element can be triggeredmanually, in particular using the instrument for placing the device ofthe invention, or else it can be triggered automatically, if said firstlink element is also connected to said blocking means in such a manneras to release first link element once said blocking means have beenlocked.

That is why, in a preferred embodiment, said first link element issuitable for co-operating with said blocking means so that said firstlink element is released once said strands of thread have been blockedtogether with the help of said blocking means.

In a second variant embodiment of the invention, the device includesresilient junction means and it is suitable for co-operating with aplacing instrument to which it is preferably secured via a top portioncorresponding to said blocking zone, such that:

-   -   prior to said contact zone coming into contact with said tissue,        said resilient junction means are at rest and said contact zone        and said blocking zone are in the remote position (L+a);    -   when said contact zone is caused to exert pressure on said        tissue to be sutured, said resilient junction means are in        compression and the distance between said blocking zone and said        contact zone decreases down to a said initial distance (L) as        controlled by a said minimum spacer element, which element is        preferably secured to said placing instrument, said bearing        contact zone coming into abutment against said spacer element of        said placing instrument; and    -   said final distance (L±b, b<a) is obtained by co-operation        between said spacing instrument and said device, preferably by        separating said placing instrument from said suture device.

The term “resilient junction means at rest” is used to mean that saidresilient means are not under stress.

More particularly, said junction means are made of a material thatpresents elasticity, and the displacement of said blocking zone and saidcontact zone is controlled by the placing instrument which is secured tosaid blocking zone in such a manner that:

-   -   when pressure is exerted on said blocking zone, said blocking        zone can be moved from a remote position (L+a) to a first close        position (L) corresponding to said initial distance, in abutment        against said first spacer element of said placing instrument, in        which it is possible to block the two strands of thread together        under arbitrary tension exerted by the surgeon, which tension        may be greater than or less than said first predetermined        tension value; and    -   the suture thread is tensioned after said blocking and after the        placing instrument has been withdrawn, when the pressure exerted        on said blocking zone is released by moving said blocking zone        towards a second adjusted position (L±b), which position may be        closer (L−b) than said first position if the tension exerted on        the thread by the surgeon was greater than said predetermined        tension value, or it may be further away (L+b) than said first        position if the tension exerted on the thread by the surgeon was        less than said predetermined tension value.

According to another advantageous characteristic of the device of theinvention, it is of a shape such that after suturing has been performed,the thread is unencumbered so as to be capable of being cut between saidblocking zone and said suture orifices in said tissue, and preferablybetween said blocking zone and said contact zone.

This makes it easier to cut the threads, and also to eliminate thesuture should that be necessary. The reversible nature of the suturingperformed by the device makes it possible, in the event of wrongpositioning, to return to a preceding situation almost instantaneously,thus giving the surgeon greater freedom of choice and freedom of actionthroughout the time surgery is taking place.

According to another advantageous characteristic of the device of theinvention, it includes guide means enabling the two strands of thread tobe held in a position where they are spaced apart from each otherlaterally at the suture orifices in said tissue.

Said guide means are more particularly suitable for maintaining the twothreads in a spaced-apart position when tension is exerted on saidthread after the strands of thread have been connected together at saidblocking zone by said blocking means. It will be understood that saidguide means then make it possible to avoid tearing the tissue at theorifices where the thread passes through said tissue when tension isexerted on the thread after the ends of the thread have been blockedtogether.

More particularly, the device of the invention has said guide means atsaid thrust surface defining said zone of contact between the device andthe tissue.

In a preferred embodiment of the invention, said guide means comprise atleast one notch formed in said bearing surface defining said contactzone.

Also preferably, beneath a said notch, said bearing surface has a pieceof fabric made of biocompatible materials and suitable for having twostrands of thread pass therethrough, and suitable for keeping themspaced apart. The fabric may be constituted in particular by a syntheticmaterial that facilitates hemostasis and that preserves the integrity ofthe biological or synthetic tissues to be sutured. In particular, it anbe constituted by a piece of vascular prosthesis, a compress, or a swab.

In the conventional technique for maintaining lateral spacing betweenthe orifices in a conventional suture, the surgeon uses a “pledget”.This is a piece of fabric, in particular made of Dacron® or Teflon®,through which the surgeon passes the two strands of thread separately,and it acts as an intermediary between the knots and the tissue to besutured.

In the invention, the covering of biocompatible material acting as meansfor guiding and separating the strands of the suture thread where theyleave the sutured tissues also acts as a traditional pledget, but it isintegrated in the device, thereby making contact between the device andthe tissue gentler and less traumatic, and performing the pledgetfunction of facilitating hemostasis and preserving the integrity of thesutured tissues.

In a preferred embodiment, said blocking means comprise two blockingsurfaces which can move between a spaced-apart position in which it ispossible to insert said strands of suture thread between said twoblocking surfaces, and which is suitable for blocking the strands ofthread together by friction between the threads and said two blockingsurfaces once the surfaces are in the close-together, blocking position,with the displacement of said two blocking surfaces between saidspaced-apart position and said close-together position preferablyautomatically triggering said tensioning of the threads.

It is advantageous for the suture threads to be blocked together by afriction force rather than by a pinching force which would imply a riskof the threads breaking. For this purpose, said blocking surfaces needto present the following characteristics:

-   -   the material used for making the blocking surfaces must be        compatible with the material constituting the suture threads;    -   the surfaces must be as large as possible in order to maximize        contact area with the threads, thereby increasing the friction        force; and    -   the surfaces must not present sharp angles that might cut the        thread.

In a preferred embodiment of the device of the invention, said blockingof the strands of thread using said blocking means is suitable for beingtriggered automatically.

Automatic triggering of the blocking mechanism can take place via theinstrument that is used for inserting and placing the device of theinvention at the suture.

More particularly, the automatic triggering of said blocking means cantake place when the device of the invention is put into contact with thetissues for suturing with a bearing force that is greater than a secondpredetermined value lying in the range 0.2 N to 20 N, and in particulargreater than 10 N. This bearing force estimated at 10 N corresponds tothe force developed by a surgeon when pulling on the suture threadswhile making a first knot in a traditional suture for performinganastomosis of the abdominal aorta. The magnitude of this bearing forcenaturally varies with the type of surgery being performed and with thetype of suture thread being used.

Advantageously, said blocking means comprise two jaws that areelastically connected together and that form said blocking surfaces,which jaws are spaced apart by a second spacer element, and said secondspacer element is suitable for being released by being disengaged or bybeing broken, thereby allowing said blocking surfaces to move towardseach other and block said strands of thread.

Said second spacer element may be an element of said suture deviceitself, or of said placing instrument.

More particularly, said second spacer element is suitable for beingreleased automatically, preferably by said placing instrument pressingagainst said second spacer element, whenever said bearing surface of thedevice exerts pressure on the tissues that is greater than a said secondpredetermined value preferably lying in the range 0.2 N to 20 N, andmore preferably of at least 10 N.

Still more particularly, said second spacer element is suitable forbeing released by automatically triggering the release of said firstlink element between said blocking zone and said contact zone of thedevice so that said zones adopt said adjusted final distance thatenables a said control tension to be exerted on said thread.

In an advantageous embodiment of the present invention, the bearingforce exerted at the base of the device of the invention against thetissues enables said second spacer element to be released, therebypreferably triggering tensioning of the thread after said strands ofthread have been blocked, tensioning being at a said first tensionvalue, by releasing, where appropriate, said first link element formaintaining the fixed spacing between said blocking zone and saidcontact zone at said initial distance, so that said blocking and contactzones adopt a said adjusted distance.

In another embodiment, said blocking means comprise projecting elementsthat are preferably of circular section, more preferably of cylindricalshape, having the ends of the strands of thread for connection togetherwound thereabout. More particularly, said blocking can be achieved bymoving said projecting elements towards each other or away from eachother.

In another embodiment, said blocking means include a blocking orifice insaid blocking zone, said blocking orifice co-operating with a secondblocking element comprising a screw, a rivet, a pushbutton, or indeed ajam cleat.

In another embodiment, said blocking means comprise means for sticking,melting, heat-sealing, or crimping the two strands of thread together ina said blocking zone.

Preferably, the blocking between said strands of thread must be capableof withstanding a traction force lying in the range 0.5 N to 50 N, andin particular of about 20 N to 30 N, with the suture thread breaking ata higher force.

If the shape of the device of the invention, and if particular of saidjunction element between said bearing surface and said blocking zone,does not make it possible to provide access for cutting the threads inorder to undo the suture and remove the device, an alternative is toprovide blocking means in such a manner that the blocking means can beunlocked with an instrument, thereby releasing the threads from beingblocked together.

In the present invention, the term “implantable device” is used to meana device of size and of biocompatible constituent materials that enableit to be implanted in the human body, and more particularly implantedfor the long term, inside the human body, i.e. for a duration of morethan 30 days.

Similarly, in the present invention, the term “implantable by aminimally invasive approach” is used to mean that the device of theinvention is sufficiently small to enable it to be implanted by aminimally invasive approach, and more particularly through a trocar, inparticular a trocar having a diameter lying in the range 2 mm to 20 mm.Still more particularly, the device of the invention presents dimensionsin terms of height and width that lie in the range 2 mm to 20 mm, andpreferably in the range 5 mm to 10 mm.

A device of the invention can be used in minimally invasive surgery, inparticular in robot-assisted surgery, and also in conventional surgery.Depending on the degree of miniaturization of the device, use thereofcan be envisaged in various types of minimally invasive surgery, suchas, for example:

-   -   abdominal surgery;    -   cardiothoracic surgery; and    -   cervical surgery.

In a more advantageous embodiment, the device of the invention presentsa mechanical structure that is simple and comprises, at least in part,and preferably completely, said bearing element, said blocking means,and said controlled tensioning means, forming a single integrally-formedmechanical part.

As mentioned above, the material constituting the elements making up thedevice of the invention is a biocompatible material. Materials of thistype can be metals, plastics, or composites, and are known to the personskilled in the art. Some are given by way of example in the detaileddescription below.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the present invention appear inthe light of the following detailed description of embodiments givenwith reference to FIGS. 1 to 11, in which:

FIGS. 1 to 4 show a first variant embodiment of a U-shaped suture deviceof the invention, with the device being shown in FIG. 1 held stationaryon an ancillary 12 prior to being put into place. In FIG. 2, the deviceis shown at the moment the ancillary presses against the top portion ofthe device immediately prior to the threads being blocked together. InFIG. 3, the device is shown while blocking is taking place. In FIG. 4,the ancillary 12 has been removed and the suture device 11 is shownafter blocking has taken place.

FIGS. 5 to 7 show a second variant embodiment of a U-shaped suturedevice. In FIG. 5, the device is shown held in place in its placingancillary 12. Said ancillary is shown in face view in FIG. 6 and in sideview in FIG. 7.

In FIGS. 1-3 and 5-7, said ancillary is shown purely diagrammatically,and only the bottom portion thereof that co-operates with the device.

FIGS. 8 to 10 show a second variant embodiment of a suture device of theinvention comprising two plates interconnected by a conical spring whichis shown in its initial position prior to blocking in FIG. 8, then inits blocking position in FIG. 9, and finally in the tensioning positionof the device in FIG. 10.

FIG. 11 shows a variant configuration for the notch 7 ₁ constituting theguide means in said bearing surface 4 ₁,

In FIGS. 1 to 11, the suture device of the invention is showndiagrammatically so as to present its various component elements moreclearly.

MORE DETAILED DESCRIPTION

In a first variant embodiment shown in FIGS. 1 to 7, the device of theinvention is U-shaped and comprises:

-   -   a bottom first branch 4 ₁ defining a said bearing surface and        contact zone against said tissue;    -   a top second branch 4 ₂ comprising said blocking zone and        secured to or co-operating with said blocking means 2; and    -   a junction element 4 ₃ between said first and second branches 4        ₁, 4 ₂ and made of a semirigid material presenting a said degree        of elasticity. The junction element is straight or preferably        curved so as to provide a hairpin junction between said two        branches.

The entire device can be made of biocompatible materials that aremetals, plastics, or composites, and in particular it can be made of316L steel, of titanium, or of polypropylene.

In this embodiment, the space between the two branches of U has only twostrands of thread passing therethrough, which strands can therefore becut in this location, should that be necessary.

Said first tension value exerted by the device depends on a dimensionalparameter, in particular on the section of the hairpin junction elements4 ₃ and on the nature of the material used. It is preferably about 2 Nfor an application to surgery of the abdominal aorta using threads madeof polypropylene 4.0.

FIGS. 1 to 4 are diagrams showing a suture device of the invention thatis U-shaped in this first embodiment described below.

The top branch 4 ₂ defines a blocking zone having two jaws 2 that areinitially open, i.e. spaced apart, serving to block the threads 3 ₁ and3 ₂ by the threads rubbing against two adjacent and complementarysurface 2 ₁ and 2 ₂ on respective ones of the two jaws 2 when said twocomplementary surfaces 2 ₁ and 2 ₂ close against each other with thethreads thus being blocked between them.

The two jaws 2 are made of polypropylene, for example, and they areresiliently connected together, their two complementary surfaces 2 ₁ and2 ₂ being initially held spaced apart by a spacer tab 2 ₃. In this case,the spacer tab 2 ₃ is secured to one of the jaws 2 at one end, while itsother end carries a tooth 2 ₅ which co-operates with a notch 2 ₄ in thesecond jaw so that said two complementary surfaces 2 ₁ and 2 ₂ closeagainst each other when said tooth 2 ₅ of the tab 2 ₃ is disengaged fromthe notch 2 ₄, thereby releasing the two jaws 2.

Said complementary structures 2 ₁ and 2 ₂ of the two jaws 2 arepreferably of curved shape, forming on their surfaces paths towards thethreads that are as long as possible so as to maximize the contact areaswith the threads, so that the threads are blocked by friction thanrather by clamping, so as to avoid damaging the threads.

The bottom branch 4 ₁ includes a central notch 7 ₁, itself covered onits underside by a pledget 7 ₂ made of Dacron® or Teflon® serving tohold the threads 3 ₁ and 3 ₂ apart at the orifices 6 ₁ and 6 ₂ wherethey leave the tissues for suturing together, the spacing between equalto 3 mm to 5 mm, for example, thereby preserving the integrity of saidtissues and facilitating hemostasis.

The bottom branch 4 ₁, forming the zone of contact with the tissue, isconnected to the top branch forming the blocking zone 4 ₂ by theresilient junction zone 4 ₃ and also by a first link element or link rod5 ₁. Said link rod 5 ₁ has one of its ends secured to said bottom branch4 ₁, and at its other end it carries a second tooth 5 ₃ whichco-operates with a second notch 2 ₆ in the top branch 4 ₂, said secondnotch 2 ₆ being a lateral notch, i.e. a notch in one of the sides of thetop branch 4 ₂.

The suture device 1 ₁ co-operates with an ancillary 1 ₂ on which it isheld stationary. One of the jaws 2 (or both jaws 2) of the top branch 4₂ is (or are) held relative to the ancillary 1 ₂, e.g. in a hollowhousing 8 ₁ in which the jaw 2 is initially fitted and/or blocked.

So long as the link rod 5 ₁ is not engaged in said lateral second notch2 ₆ of the top branch 4 ₂, and in the absence of any blocked thread, thetop and bottom branches 4 ₁ and 4 ₂ are in a natural rest position inwhich they are spaced apart by a distance L+a.

When the link rod 5 ₁ is engaged in said lateral second notch 2 ₆ of thetop branch, the device takes up a compressed state, and the distancebetween the two branches 4 ₁ and 4 ₂ is reduced, and corresponds to saidinitial distance L immediately before and during blocking.

The way in which the suture device of the invention is put into placeand implemented is as follows:

1) The surgeon takes the suture device 1 ₁ secured to the ancillary 1 ₂at the end of a rod of the ancillary 1 ₂, and places it close to thesuture zone.

2) The surgeon perforates the pledget 7 ₂ in the notch 7 ₁ of the bottombranch 4 ₁ with the suture threads 3 ₁ and 3 ₂, passing through thepledget at 6 ₁ and 6 ₂. Passing two needles connected to the suturethreads 3 ₁ and 3 ₂ through the pledget 7 ₂ is an act that is performedhabitually by surgeons and presents no difficulty. Once the threads passthrough the pledget 7 ₂, there is no longer any risk of the threadsbecoming tangled together. Furthermore, because the blocking mechanismis constituted by two jaws 2 that are held spaced apart by the spacertabs 2 ₃, it is easy to insert the thread into the blocking mechanism,i.e. into the space defined by the two spaced-apart jaws 2 and saidspacer tab 2 ₃.

3) Subsequently, the suture device can be lowered by the device slidingalong the threads 3 ₁ and 3 ₂ passing through the pledget 7 ₂ and thespace defined between the two jaws 2 and the spacer tab 2 ₃ (see FIG.1). The threads 3 ₁ and 3 ₂ are then under low tension and the distancebetween the two branch or blocking zone 4 ₂ and the bottom branch orcontact zone 4 ₁ corresponds to said initial distance L which ismaintained by the connection rod 5 ₁.

4) On coming into contact with the tissues that are to be suturedtogether, the surgeon presses the device 1 ₁ against the tissues to besutured by means of the placing instrument 1 ₂. Once the applied thrustforce reaches a predetermined level having a said second value, and inparticular a value of 10 N, the pusher element 8 ₂ of the ancillaryprovided for this purpose comes to press against the spacer tab 2 ₃,thereby causing the spacer tab 2 ₃ to bend in such a manner that itstooth or projection 2 ₅ moves out from the notch 2 ₄ (FIG. 2), therebytriggering the two resiliently interconnected jaws 2 to move towardseach other and press against each other so as to block the threads 3 ₁and 3 ₂ between their complementary surfaces 2 ₁, 2 ₂ (FIG. 3). At thisstage, the threads 3 ₁ and 3 ₂ are blocked at a tension value thatcorresponds to the tension initially exerted by the surgeon on thethreads while pushing the device against the tissues to be suturedtogether, and the distance between the contact zone of the bottom branch4 ₁ and the blocking zone of the top branch 4 ₂ is L. Simultaneously, orimmediately thereafter, the suture device firstly separates from theancillary and secondly causes the link rod 5 ₁ between the bottom andtop branches 4 ₁ and 4 ₂ to become disengaged so that the distancebetween the top and bottom branches 4 ₁ and 4 ₂ can become adjusted to asaid final distance L′=L±b.

The resilient junction element 4 ₃ between the bottom branch 4 ₁ and thetop branch 4 ₂ is designed in such a manner that when the distancebetween the bottom and top branches 4 ₁ and 4 ₂ is L±b with b<a, the twobranches exert a tension having said first predetermined tension value,in particular lying in the range 0.1 N to 10 N, and more particularlyhaving a value of 2 N, as explained above.

5) The threads can then be cut a few millimeters above said blockingzone 4 ₂, in particular 5 mm to 6 mm above, with the threads thus beingblocked together and under tension at said selected first predeterminedvalue as obtained as a function of the way in which the suture device ismade and in particular the way in which the junction element 4 ₃ betweenthe bottom and top branches 4 ₁ and 4 ₂ is made.

The threads 3 ₁ and 3 ₂ are thus blocked together automatically when thesuture device comes into contact with the tissues that are to be suturedtogether and a bearing force is exerted on said device having a saidsecond predetermined value, which in this case is 10 N. This value of 10N corresponds to the force exerted by a vascular surgeon when pulling onthe suture threads in order to tie a knot in a suture in the usual way.It should be observed that, prior to blocking, this initial 10 N bearingforce is supported by the link rod 5 ₁, which keeps the bottom and topbranches 4 ₁ and 4 ₂ spaced apart in spite of said bearing force. Oncethe spacer tab 2 ₃ has been disengaged and the two jaws 2 have beenreleased, the movement towards each other of the resiliently-connectedjaws 2 causes the threads to be blocked together and causes the distancebetween the bottom and top branches 4 ₁ and 4 ₂ to be come adjusted to afinal distance (L±b where b<a), at which distance said branches exert atension on the blocked-together threads, which tension has said firstpredetermined value.

In addition, and advantageously, the ancillary 1 ₂ includes a spacerelement 5 ₂ which prevents the bottom branch 4 ₁ with the device contactzone from moving too close to the top branch 4 ₂ with the blockingzones, i.e. approaching to a distance of less than L, so that the bottombranch 4 ₁ or contact zone 4 ₁ can be pressed against the tissue forsuturing without any risk of leading to anticipated disengagement, inparticular by the link rod 5 ₁ twisting.

It should be observed that the space between the bottom branch 4 ₁ andthe top branch 4 ₂ gives access for cutting the threads 3 ₁ and 3 ₂,should that be necessary in order to deactivate the suture device 1 ₁.

The automatic triggering of the mechanism for blocking the threads 3 ₁and 3 ₂, followed by the tensioning of the blocked-together threads at asaid first predetermined tension value, thus relieves the surgeon of anyneed to perform a whole set of acts, but without leading to anydifficulty.

In FIGS. 5 to 7, there is shown a second embodiment of the first variantof a U-shaped suture device, which differs from the first variant asshown in FIGS. 1 to 4 as follows:

-   -   1) said second spacer element 2 ₃, for spacing apart the two        jaws 2 constituting said blocking zone, no longer forms a part        of the suture device 1 ₁ proper, but is integrated in the        placing instrument 1 ₂; and    -   2) the top and bottom branches of the U-shape respectively        defining said blocking zone 4 ₂ and said contact zone 4 ₁ are        not initially interconnected by a link rod 5 ₁, but are held        spaced apart by a said first spacer element 5 ₂, which forms an        integral portion of the placing instrument 1 ₂.

As in the first variant of FIGS. 1 to 4, the suture device 1 ₁ of FIGS.5 to 7 is held stationary on the placing instrument 1 ₂ via saidblocking zone 2. More particularly, each of the jaws 2 is held in thespaced-apart position using the spacer bar 2 ₃ of the placing instrument1 ₂, with the ends 2 ₁₀ and 2 ₁₁ of the bar being received in grooves 2₇ in each of the two jaws 2. The two jaws 2 in the spaced-apart positionhave their bottom faces coming to bear against the top faces at the topends of each of said two first spacer elements 5 ₂ of the ancillary, andthe top faces of the two jaws 2 are held by a transverse bar 9 ₁ of theancillary 1 ₂.

It should be observed that initially, prior to coming into contact withthe tissues to be sutured together, the bottom branch 4 ₁ defining thecontact zone of the device need not necessarily press against the bottomend of said spacer element 5 ₂ of the ancillary. The height of saidspacer element 5 ₂ of the ancillary corresponds to said initial blockingdistance L, such that said first spacer element 5 ₂ of the ancillary 1 ₂makes it possible, when the contact zone 4 ₁ of the device is broughtinto contact with the tissues to be sutured together, and is thenpressed thereagainst, to limit the bending of the intermediate junctionelement 4 ₃ of the device so as to maintain the distance between theblocking zone 4 ₂ and the contact zone 4 ₁ equal to said initialdistance L. This initial distance L between the top blocking zone 4 ₂and the bottom contact zone 4 ₁ corresponds to the mean value of thespacing (L±b) that needs to be maintained between these two zones of thedevice in order to ensure that the suture threads have said firstpredetermined tension value after being blocked together.

At rest, prior to being put into place, the two jaws 2 are spaced apartby the spacer rod 2 ₃ of the ancillary, with the ends of the rod beingreceived in the grooves 2 ₇ in each of the two jaws 2. The grooves 2 ₇in the jaws 2 are symmetrical and designed to be of depth that variesfrom a deep end 2 ₈ towards a shallow end 2 ₉, such that:

-   -   Initially, the ends 2 ₁₀ and 2 ₁₁ of the spacer rod 2 ₃ are        received in the deep ends 2 ₈ of the grooves 2 ₇. In this        position, the surgeon can perforate the fabric acting as the        pledget 7 ₂ in the notch 7 ₁ with the suture threads, and can        then cause the threads to pass through the space defined between        the two jaws 2 and the spacer rod 2 ₃ of the ancillary. The        assembly can then be put into contact with the tissues to be        sutured without the threads running the risk of escaping since        they slide through the pledget 7 ₂ and in the space defined        between the two jaws 2 and the spacer rod 2 ₃.    -   Thereafter, on coming into contact with the tissues to be        sutured together, pressure P is exerted in the direction NN′ on        the placing instrument 1 ₂, which pressure is transmitted to the        spacer rod 2 ₃ which is in a position such that the axis NN′        passes through the middle of the rod 2 ₃. As a result, the ends        2 ₁₀ and 2 ₁₁ of the spacer rod 2 ₃ slide along the grooves 2 ₇        from the deep ends 2 ₈ thereof towards their shallow ends 2 ₉,        with the spacing between the two jaws 2 increasing.    -   Then, once the thrust exerted on the ancillary reaches a bearing        force having a said second predetermined value, e.g. of 10 N,        the jaw spacer rod 2 ₃ escapes completely from the grooves 2 ₇.        The two jaws 2, whose complementary surfaces 2 ₁ and 2 ₂ are        connected together resiliently, then move towards each other,        thereby blocking together the suture threads 3 ₁ and 3 ₂. At the        instant blocking takes place, the contact zone 4 ₁ and the        blocking zone 4 ₂ constituted by the two close-together jaws 2        are spaced apart by said initial distance L corresponding to the        height of said first spacer element 5 ₂ of the ancillary 1 ₂.

The width of the two jaws 2 after they have moved together in this wayis less than the distance l between the top ends of said two firstspacer elements 5 ₂ of the ancillary 1 ₂, so the ancillary can bewithdrawn and separated from the device by being pulled upwards, thespacing between the contact zone 4 ₁ and the blocking zone 4 ₂ then nolonger being controlled by said first spacer element 5 ₂ of theancillary 1 ₂, whereupon it is said tension of said first predeterminedvalue that is exerted by the top and bottom branches 4 ₁ and 4 ₂ of thedevice under the effect of the elasticity of the junction element 4 ₃that acts on the blocked-together threads, and in particular a saidfirst tension value of 2 N.

In a second variant embodiment of the invention as shown in FIGS. 8 to10, the device is constituted by:

-   -   a first plate 4 ₁ defining a said bearing surface for bearing        against said tissue;    -   a second plate 4 ₂ including said blocking zone; and    -   said first and second plates 4 ₁ and 4 ₂ are connected together        by a resilient junction element comprising a spring blade or        wire.

More particularly, a device of the invention comprises:

-   -   a said spring wire 4 ₃ defining a frustoconical envelope;    -   said first plate 4 ₁ at the end of said spring that corresponds        to the large base of said truncated cone formed by the spring;    -   said second plate 4 ₂ at the end of said spring beside the small        base of said truncated cone formed by said spring; and    -   preferably, said spring 4 ₃ is suitable for being received in        the empty central space thereof when it is compressed by moving        said first and second plates towards each other.

It will be understood that in this embodiment, the suture threads passinside the spring between said first and second plates.

The blocking zone 4 ₂ is preferably smaller in size than the contactelement 4 ₁. In its compressed state, the spring occupies a minimumamount of space in the height direction. The dynamometer behavior isprovided by the predefined stiffness of the spring.

This second variant embodiment with a frustoconical spring 4 ₃ differsfrom the U-shaped first embodiment of FIGS. 1 to 4 essentially by thefact that the intermediate junction element 4 ₃ is constituted by a saidspring 4 ₃ of frustoconical envelope.

Otherwise, the blocking zone 4 ₂ is likewise constituted by twointerconnected jaws. Said blocking zone 4 ₂ is constituted by tworesiliently-connected jaws 2 that are held spaced apart by a spacer rod2 ₃ secured at one of its ends to one of the two jaws and co-operatingat its opposite end with a notch 2 ₄ in the second jaw. The two jaws 2are thus held spaced apart and can thus be held in place on a placinginstrument 1 ₂. Thereafter, when a bearing force is exerted on thespacer rod 2 ₃, it bends and comes out of the notch 2 ₄ in the secondjaw 2, such that the complementary surfaces 2 ₁ and 2 ₂ on the two jaws2 can move towards each other and block the threads (FIG. 9).Simultaneously, the connection rod 5 ₁ can become disengaged so that thedistance between the first plate 4 ₁ and the second plate 4 ₂ is thencontrolled solely by the tension exerted by the connection spring 4 ₃.The connecting spring 4 ₃ is designed in such a manner that it exerts atension having a said first value, in particular 2 N, when it goes awaysaid initial distance L between the contact and blocking zones at thetime of blocking in order to adopt a said final distance L±b, asexplained above.

In this second variant embodiment, the pressure exerted on the ancillary1 ₂ thus causes the suture threads to be blocked together, after whichit triggers tensioning of the suture threads once blocked together at asaid first predetermined value.

In both variant embodiments shown in FIGS. 1 to 10, the suture device issuch that:

-   -   at rest, the distance between said contact zone 4 ₁ and said        blocking zone 4 ₂ is equal to L+a;    -   the distance between said contact zone 4 ₁ and said blocking        zone 4 ₂ is equal to L when the device is in contact with the        tissues to be sutured together and in a position ready for        blocking, possibly with the device being held in place on its        placing instrument (first variant); and    -   the resilience of the various components of the device, and in        particular of the intermediate junction element 4 ₃ is designed        so that when the distance between said contact zone 4 ₁ and said        blocking zone 4 ₂ lies in the range L−b and L+b (where b<a), a        force having said first value, and in particular a value of 2 N,        is needed to keep the compressed device at said distance L±b.

By way of illustration, values for L, a and b can be as follows:

-   -   L=2 mm, a=1 mm, b=0.5 mm.

Thus, in these two variant embodiments, two situations can arise whilethe surgeon is putting the suture device into place:

1) First Situation

When blocking is triggered, the tension being exerted by the surgeon onthe suture threads is equal to T₁ where T₁<T₀ (T₀=the firstpredetermined tension value, e.g. 2 N), and the length of the strands ofthread between said contact zone and said blocking zone is L.

In this first situation, when tensioning is triggered after blocking hastaken place, the device is no longer held by the placing instrument 12and seeks to expand since it is subjected only to the action of thetension T₁ in the threads, so the distance extending between saidcontact zone 4 ₁ and said blocking zone 4 ₂ as constituted by the twoclose-together jaws 2 will take on a value greater than L, i.e. L+b,where b<a. The tension exerted on the suture threads by the device isthen equal to T₀ and the strands of thread prevent the device fromexpanding beyond the distance L+b, where b corresponds to the extent towhich the threads lengthen under the effect of the difference in tensionT₀−T₁.

2) Second Situation

When blocking is triggered, the tension exerted by the surgeon on thesuture threads immediately prior to blocking is equal to T₁>T₀ and thelength of the strands of thread between said contact zone and saidblocking zone is L.

When, after blocking, tensioning of the threads by the device istriggered, the device will compress under the action of the tension T₁in the threads, and the distance between said contact zone and saidblocking zone will take on a value that is less than L, i.e. L−b, whereb<a. The tension exerted by the device on the threads is thus equal toT₀ and the device prevents the threads from compressing beyond thedistance L−b, where b corresponds to the shortening of the strands ofthread under the effect of the difference in tension T₁-T₀.

FIG. 11 shows a variant embodiment of the guide means in said contactzone 1 having a said notch 7 ₁ that is in the form of a middle slot onthe middle axis of said blocking zone together with two zones 7 ₃ thatare disposed symmetrically about said middle slot, said two saidsymmetrical zones 7 ₃ comprising or defining retaining abutments forholding the two strands of thread 3 ₁ and 3 ₂ in a spaced-apart positionwhere they pass through said zones, respectively. Said symmetrical zone7 ₃ of the notch 7 ₁ are spaced apart so as to allow the two strands ofthread 3 ₁ and 3 ₂ to be tensioned on the axes of said suture orifices 6₁, 6 ₂ so as to avoid applying any stresses to said suture orifices whenexerting tension on the thread.

In the various embodiments, the suture device of the invention whenapplied to minimally invasive surgery can be put into place, forexample, using a placing instrument 1 ₂ acting through a trocar having adiameter of 2 mm to 12 mm, said device having a said bearing surface anda said blocking zone which lie within a rectangular area of 2 mm² to 40mm² and that are spaced apart by a maximum height of 10 mm.

1. An implantable device for semiautomatic suturing using a surgicalthread (1 ₁), the suturing enabling biological and/or artificial tissuesto be united, the device comprising blocking means (2) enabling twostrands (3 ₁, 3 ₂) of the thread of a suture to be connected together ina blocking zone (4 ₂), and comprising a bearing element having a bearingsurface (4 ₁) for bearing against the tissues to be sutured together,the device being characterized in that it further comprises controlledtensioning means (4 ₃) for applying controlled tensioning to saidthread, and suitable for exerting a tension having a first predeterminedtension value after the two strands of said thread have been blockedtogether using said blocking means (2), with the junction between saidbearing element (4 ₁) and said blocking zone (4 ₂) of the device beingprovided by said controlled tensioning means (4 ₃).
 2. A deviceaccording to claim 1, characterized in that the blocking of said strandsof thread using said blocking means is suitable for automaticallytriggering said tensioning of the threads to a said predeterminedtension value, preferably lying in the range 0.1 N to 10 N.
 3. A suturedevice according to claim 1, characterized in that said controlledtensioning means (4 ₃) enable the distance between said blocking zone (4₂) and said contact zone (4 ₁) in contact with the tissue to be adjustedbetween: an initial distance (L) in which said two ends of the strands(3 ₁, 3 ₂) of thread can be blocked together with the thread being at atension that is preferably low; and a final distance (L′=L±b) suitablefor exerting a said controlled tension having a said first predeterminedtension value.
 4. A suture device according to claim 3, characterized inthat said tensioning means (4 ₃) comprise resilient junction meansbetween said contact zone (4 ₁) and said blocking zone (4 ₂) so as toenable the distance between said contact zone (4 ₁) and said blockingzone (4 ₂) to be adjusted between: a controlled initial distance (L) inwhich the spacing between said contact zone (4 ₁) and said blocking zone(4 ₂) is controlled by a first link element (5 ₁) and/or a first spacerelement (5 ₂), and said initial distance (L) corresponding to a distancein which said blocking zone (4 ₂) and said contact zone (4 ₁) are in aclose-together position by applying compression compared with aspaced-apart, rest position (L+a); and said final adjusted distance(L′=L±b) corresponds to a position of force equilibrium in which thedistance between said contact zone (4 ₁) and said blocking zone (4 ₂) isno longer controlled by a said first link element (5 ₁) and/or a saidfirst spacer element (5 ₂).
 5. A device according to claim 4,characterized in that said initial distance (L) between said blockingzone (4 ₂) and said contact zone (4 ₁) can be obtained using a firstlink element (5 ₁) suitable for initially connecting said blocking zone(4 ₂) and said contact zone (4 ₁) of the device, and said final distance(L′=L±b) of said first blocking zone (4 ₂) relative to said firstcontact zone (4 ₁) can be implemented by releasing said first linkelement (5 ₁).
 6. A device according to claim 5, characterized in thatsaid first link element (5 ₁) is suitable for co-operating with saidblocking means (2) in such a manner that said first link element (5 ₁)is released once said strands of thread (3 ₁, 3 ₂) have been blockedtogether using said blocking means (2).
 7. A suture device (1 ₁)according to claim 4, characterized in that said device (1 ₁) issuitable for co-operating with a placing instrument (1 ₂) to which it issecured, preferably via a top portion corresponding to said blockingzone (4 ₂) in such a manner that: prior to said bearing surface (4 ₁)coming into contact with said tissue, said resilient junction means (4₃) are at rest, and said bearing surface (4 ₁) and said A blocking zone(4 ₂) are in a spaced-apart position; when said contact zone (4 ₁) ispressed against said tissue for suturing, said resilient junction means(4 ₃) are put into compression and the distance between said contactzone (4 ₁) and said blocking zone (4 ₂) decreases to a said initialdistance (L) controlled by a said first minimum spacer element (5 ₂),which element is preferably secured to said instrument (1 ₂), saidbearing surface (4 ₁) coming into abutment against said first spacerelement (5 ₂) of said instrument; and said final distance (L′) isobtained by co-operation between said placing instrument (1 ₂) and saiddevice (1 ₁), preferably by separating said placing instrument (1 ₂)from said suture device (1 ₁).
 8. A device according to claim 2,characterized in that it is adapted for the thread to be disengaged soas to be capable of being cut between said blocking zone (4 ₂) and saidsuture orifices (6 ₁, 6 ₂) in said tissue, preferably between saidblocking zone (4 ₂) and said contact zone (4 ₁).
 9. A device accordingto any one of claim 1, characterized in that it includes guide means (7)enabling the two strands (3 ₁, 3 ₂) of thread to be held laterallyspaced apart from each other at the suture orifices (6 ₁, 6 ₂) in saidtissue.
 10. A device according to claim 9, characterized in that saidguide means (7 ₁, 7 ₂) comprise at least one notch (7 ₁) made in saidbearing surface defining said contact zone (4 ₁).
 11. A device accordingto claim 10, characterized in that said guide means comprise, on anunder-face of a said notch (7 ₁), a piece of fabric (7 ₂) ofbiocompatible material suitable for being pierced by said two strands ofthread in order to keep them spaced apart.
 12. A device according toclaim 4, characterized in that it is U-shaped, comprising: a bottomfirst branch (4 ₁) defining a said bearing surface for bearing againstsaid tissue, and including said contact zone (4 ₁); a top second branch(4 ₂) including said blocking zone and secured with or co-operating withsaid blocking means (2); and a junction element (4 ₃) between said firstand second branches (4 ₁, 4 ₂), the junction element being made of asemirigid material presenting a said elasticity, preferably being acurved junction element (4 ₃) providing a hairpin junction between saidfirst and second branches.
 13. A device according to claim 4,characterized in that it is constituted by: a first plate (4 ₁) defininga said bearing surface for bearing on said tissue, and including saidcontact zone; a second plate (4 ₂) including said blocking zone; andsaid first and second plates (4 ₁, 4 ₂) being connected together by ajunction element (4 ₃) comprising a resilient spring wire or springblade.
 14. A device according to claim 13, characterized in that: saidspring wire (4 ₃) defines a frustoconical envelope; said first plate (4₁) is placed at the end of said spring beside the large base of saidtruncated cone formed by said spring; said second plate (4 ₂) is placedat the end of said spring that is beside the small base of saidtruncated cone formed by said spring; and preferably, said spring (4 ₃)is suitable for being received in its own empty central space when it iscompressed by moving said first and second plates towards each other.15. A device according to claim 1, characterized in that said blockingmeans (2) comprise two blocking surfaces (2 ₁, 2 ₂) capable of movingbetween a spaced-apart position in which it is possible to insert saidstrands (3 ₁, 3 ₂) of thread between said two blocking surfaces (2 ₁, 2₂), and suitable for blocking said strands (3 ₁, 3 ₂) of thread togetherby friction between the threads and said two blocking surfaces (2 ₁, 2₂) once the surfaces are in a close-together, blocking position, thedisplacement of said two surfaces between said spaced-apart position andsaid close-together position automatically triggering said tensioning ofthe threads after blocking.
 16. A device according to claim 15,characterized in that said blocking of the strands of thread using saidblocking means is suitable for being triggered automatically.
 17. Adevice according to claim 16, characterized in that the automatictriggering of the blocking of said strands of thread using said blockingmeans take place when the device is pressed into contact with thetissues to be sutured together with a bearing force that is greater thana second predetermined value, preferably lying in the range 0.2 N to 20N, and more preferably greater than 10 N.
 18. A device according toclaim 14, characterized in that said blocking means comprise two jaws(2) resiliently connected together and forming respective ones of saidblocking surfaces (2 ₁, 2 ₂) which are held apart by a second spacerelement (2 ₃), said second spacer element (2 ₃) being suitable for beingreleased by being disengaged or broken so as to enable said blockingsurfaces (2 ₁, 2 ₂) to move towards each other and block said strands (3₁, 3 ₂) of thread together.
 19. A device according to claim 18,characterized in that said second spacer element (2 ₃) is suitable forbeing released automatically, preferably by pressing said placinginstrument (1 ₂) against said second spacer element (2 ₃) while saidbearing surface (4 ₁) of the device is exerting pressure on the tissuesthat is greater than a second determined value, preferably lying in therange 0.2 N to 20 N, and more preferably not less than 10 N.
 20. Adevice according to claim 17, characterized in that said second spacerelement (2 ₃) is suitable for being released by automatically triggeringrelease of said first link element (5 ₁) between said blocking zone (4₂) and said contact zone (4 ₁) of the device so that said zones adopt asaid final distance (L′=L±b) that is adjusted to allow a said firstcontrolled tension value to be exerted on said strands of thread.
 21. Adevice according to claim 1, characterized in that said bearing element(4 ₁), said blocking means (2), and said controlled tensioning means (4₃) form a single one-piece mechanical part.